> ## Documentation Index
> Fetch the complete documentation index at: https://developers.circle.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Before reading these docs, install the relevant Circle Skill to get pre-loaded context — skills are LLM-optimized and cover architecture decisions, correct flows, and common pitfalls. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills. Available skills: use-usdc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md (balances, transfers, approvals on EVM and Solana); EURC has no skill — see https://developers.circle.com/stablecoins/what-is-eurc.md; bridge-stablecoin https://github.com/circlefin/skills/blob/master/plugins/circle/skills/bridge-stablecoin/SKILL.md (crosschain transfers via CCTP, USDC, EURC, and third-party assets); use-arc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md (Arc chain config, contract deployment, USDC bridging — Arc docs: https://docs.arc.io/llms.txt); use-circle-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md (choose wallet type); use-developer-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md (custodial wallets for payouts and treasury); use-user-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md (embedded wallets with Web2 login); use-modular-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md (smart contract wallets with passkeys and ERC-4337); use-gateway https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md (unified USDC balance, nanopayments); use-smart-contract-platform https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md (deploy, interact, monitor contracts). Pair any skill with the Circle MCP server for live SDK signatures, contract addresses, and chain IDs: {"mcpServers":{"circle":{"url":"https://api.circle.com/v1/codegen/mcp"}}}.
> Read the product overview first. Each product has an overview explaining when and why to use it. Read it before quickstarts.
> Pick the right wallet type. Developer-controlled (you hold keys), user-controlled (end user holds keys via PIN/social login), or modular (smart contract wallets with passkeys). See https://developers.circle.com/wallets.md.
> Use CCTP V2 for crosschain transfers. CCTP natively transfers USDC and EURC via burn-and-mint, and supports permissionless wrapping of third-party assets via lock-and-mint. V1 is legacy; always use V2 unless V1 is specified or the chain requires it (Noble, Sui, and Aptos still require V1). Migration guide: https://developers.circle.com/cctp/migration-from-v1-to-v2.md.
> Use Bridge Kit for frontend bridging. Wraps CCTP with a simpler SDK for user-facing apps. Use CCTP directly for backend transfers.
> Gas Station vs Paymaster. Gas Station sponsors gas for Circle Wallet transactions. Paymaster lets users pay gas in USDC. Different use cases — read both overviews.
> Gateway Nanopayments for sub-cent payments. Gasless USDC micropayments down to $0.000001 via x402 and batched settlement. For pay-per-request APIs, AI agent payments, streaming.
> Look up USDC addresses per chain. Never hardcode — use https://developers.circle.com/stablecoins/usdc-contract-addresses.md.
> Prefer SDKs over raw API calls. Node.js and Python SDKs handle auth, retries, and errors.
> API key required. Bearer token in Authorization header. Testnet and mainnet use separate keys and may use different base URLs depending on the product.
> Set up webhooks when available. Most operations are async. Webhooks deliver transaction confirmations and state changes.
> When calling list endpoints, paginate using pageSize and pageAfter until no nextPageAfter cursor is returned—stopping at the first page silently misses records.
> Building an AI agent? Start with the Agent Stack—Circle CLI, agent wallets, and nanopayments built for autonomous use cases: https://developers.circle.com/agent-stack.md.

# Configure an ownerless token

> Set up a crosschain bridge for an existing ERC-20 using CCTP for non-USDC's ownerless token model.

After configuration, anyone can bridge the token between the home blockchain and
any destination you deploy to, without bridge governance or ownership.

## Prerequisites

Before you begin, ensure that you've:

* Deployed the ERC-20 on the home blockchain with the same number of decimals
  you intend to use on every destination
* Noted the
  [`CrossChainTokenService` address](/cctp/expanded-assets/references/contract-addresses)
  for the home blockchain and each destination blockchain
* Obtained access to the Iris fee-quote endpoint
  (`POST /v2/quote/cctpx/{tokenId}/{sourceDomain}/{destinationDomain}`)

<Warning>
  Configure the token as ownerless on exactly one blockchain—the home blockchain
  where the token's supply originates. On every other blockchain, CCTP for
  non-USDC deploys a wrapped `CrossChainToken` automatically. Configuring the same
  token as ownerless on more than one blockchain will lock supply on each with no
  mechanism to release it.
</Warning>

## Step 1. Configure the token on the home blockchain

Call
[`registerOwnerlessToken`](/cctp/expanded-assets/references/contract-reference)
on the local service with the token's address. Submit the transaction and wait
for confirmation, then read the deterministic `tokenId` from the service.

```typescript TypeScript theme={null}
const txHash = await walletClient.writeContract({
  address: serviceAddress,
  abi: serviceAbi,
  functionName: "registerOwnerlessToken",
  args: [tokenAddress],
});

await publicClient.waitForTransactionReceipt({ hash: txHash });

const tokenId = await publicClient.readContract({
  address: serviceAddress,
  abi: serviceAbi,
  functionName: "getOwnerlessTokenId",
  args: [tokenAddress],
});
```

Save the returned `tokenId`. You will use it in every subsequent step and in
every crosschain transfer. Quote remote deploys with this `tokenId`; using a
placeholder or sentinel in the Iris path causes `QuoteArgsMismatch`.

## Step 2. Quote and deploy the wrapped token on each destination

For each destination, fetch a fee quote from Iris, then call
[`deployRemoteOwnerlessToken`](/cctp/expanded-assets/references/contract-reference)
on the home service. Pass the original token address, the destination domain ID,
and the fee `claim`.

Include a `FORWARD` request with `msgType: "DeployTokenMessage"` so the quote
covers destination deploy gas and Circle can deliver the message. Iris still
expects a positive `amount` string even for deploys.

```typescript TypeScript theme={null}
const quoteRes = await fetch(
  `${IRIS_BASE}/v2/quote/cctpx/${tokenId}/${sourceDomain}/${destinationDomain}`,
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      amount: "1",
      feeToken: zeroAddress,
      requests: [
        {
          type: "FORWARD",
          params: {
            msgType: "DeployTokenMessage",
            autoExecuteHookData: false,
          },
        },
      ],
    }),
  },
);
if (!quoteRes.ok) throw new Error(await quoteRes.text());
const { signedQuote, feeTotalAmount } = await quoteRes.json();

const claim = {
  signedQuote,
  refundAddress: zeroAddress, // or your refund address
};

await walletClient.writeContract({
  address: serviceAddress,
  abi: serviceAbi,
  functionName: "deployRemoteOwnerlessToken",
  args: [tokenAddress, destinationDomain, claim],
  value: BigInt(feeTotalAmount),
});
```

This call sends a CCTP message that, when delivered, creates a remote
`CrossChainToken` wrapper and `TokenManager`. That wrapper is a new protocol
deployment; it is not the same contract as a native copy of your token that may
already exist on the destination.

Omit `FORWARD` only if you will self-relay in the next step.

## Step 3. Complete delivery (forwarded or self-relay)

How the deploy lands depends on the quote:

* **With `FORWARD`:** Circle typically submits `receiveMessage` on the
  destination. Poll until
  [`resolveTokenAddress`](/cctp/expanded-assets/references/contract-reference)
  returns a non-zero address on the destination service.
* **Without `FORWARD`:** Poll Iris
  `/v2/messages/{sourceDomain}?transactionHash=…` until the attestation is
  complete, then call `receiveMessage` on the destination `MessageTransmitterV2`
  yourself. See
  [Attestation Verification](/cctp/references/attestation-verification).

## Step 4. Verify the remote contracts

Once the destination has processed the message, look up the wrapped token and
its `TokenManager` on the destination service:

```typescript TypeScript theme={null}
const remoteTokenManager: `0x${string}` =
  await destinationPublicClient.readContract({
    address: destinationServiceAddress,
    abi: serviceAbi,
    functionName: "resolveTokenManager",
    args: [tokenId],
  });

const remoteToken: `0x${string}` = await destinationPublicClient.readContract({
  address: destinationServiceAddress,
  abi: serviceAbi,
  functionName: "resolveTokenAddress",
  args: [tokenId],
});
```

## Step 5. Rederive the `tokenId` from the token address

You can rederive the ownerless `tokenId` from a token address on the home
blockchain at any time:

```typescript TypeScript theme={null}
const tokenId: `0x${string}` = await publicClient.readContract({
  address: serviceAddress,
  abi: serviceAbi,
  functionName: "getOwnerlessTokenId",
  args: [tokenAddress],
});
```

Before the first outbound transfer, confirm the remote `TokenManager` rate limit
is non-zero; `rateLimit: 0` blocks all outbound transfers. See
[Configure rate limits and transfer caps](/cctp/expanded-assets/howtos/configure-rate-limits-and-caps).